Squirrel, ho!

Today marks the start of the first John Kelly’s Washington “Squirrel Week”: an entire week’s worth of columns devoted to that most common of mammals.

Common the squirrel may be — at least around these parts — but full of mystery, too. Come with us this week as we travel from the Great Plains of America to the jungles of Southeast Asia, from the arid foliage of western Africa to the snowy reaches of the Rocky Mountains — all squirrel stomping grounds.

But let us start right here in the nation’s capital, with a feature of Washington that impresses visitors as much as our glorious architecture and our bad traffic: black squirrels.

In a nutshell: Where did Washington’s black squirrels come from?

They came from Canada, specifically from Rondeau Provincial Park, a peninsula in Morpeth, Ontario, that juts like a uvula into Lake Erie.

The first batch of black squirrels — eight in number — was sent to the National Zoo in 1902 by Thomas W. Gibson, Ontario’s superintendent for parks. Smithsonian secretary Samuel P. Langley, in his report to Congress that year, wrote that the squirrels were accepted “in exchange,” and, indeed, checking Canadian records, Answer Man discovered that Rondeau park received an unspecified number of gray squirrels from the Smithsonian. (They are “doing nicely,” reported park caretaker Isaac Gardiner.)

The black squirrel and the gray squirrel are the same species of squirrel: Sciurus carolinensis, a.k.a. the Eastern gray squirrel, the only difference being a color variation. The black squirrels evince a “melanistic color phase,” the recessive gene for black coloration coming to the fore.

The Canadian squirrels were released in the northwestern part of the zoo, “where they were very much at home,” according to the 1923 Proceedings of the Biological Society of Washington. “They have since been constantly in the Park, especially from the vicinity of the great flight cage to the Klingle Valley, and they have spread northward to Cleveland Park and nearly to Chevy Chase.”

The zoo also released a second batch of black squirrels, which arrived in May 1906.

Black squirrels were enough of a rarity in these parts that The Washington Post felt compelled to describe them: “The pair at the Zoo are jet black — so black that they appear shiny.”

Answer Man is pretty sure that if the National Zoo received a bunch of wild animals today, it would not do what it did then: release them into the neighborhood. Although the species was already here — and so wasn’t technically an invasive — it is kind of irresponsible, don’t you think? And yet there was precedent: Smithsonian scientists had also been releasing gray squirrels.

As the Biological Society reported: “The late Dr. Wm. L. Ralph purchased many gray squirrels and liberated them in the Smithsonian grounds, where up to the time of his death in 1907, he fed and cared for them in both fair and stormy weather with keen interest and enjoyment.” Grays were also released on the grounds of the U.S. Capitol and Department of Agriculture.

Although gray squirrels were native to this area but not as common as today (until 1906 it was legal to hunt squirrels in the District), black squirrels were new. It is likely that every black squirrel you see today is related to those Canadian immigrants.

In some areas, black squirrels compose up to 25 percent of the population.

Why has the black squirrel done so well? There are theories, but no definitive answer. Richard “Thor” Thorington Jr., curator of mammals at the Smithsonian’s National Museum of Natural History, thought it might be due to the dusky animals’ greater visibility. Many squirrels end up flattened under steel-belted radials. Could black squirrels be easier for motorists to avoid? But a check of roadkill found no discrepancy in the squash rates of black vs. gray squirrels.

Could black fur retain heat, making it easier for darker squirrels to survive a cold winter? Again, the results are “ambiguous,” Thorington reports in his classic work, “Squirrels: The Animal Answer Guide” (co-authored with Katie Ferrell).

A century after their introduction, these ebony imps are still something of a novelty. Not all neighborhoods in our area have black squirrels. (Reader Dave Martin reports that he has never seen one where he lives, in Chantilly. Have you?)

As for the appeal of squirrels, Answer Man will simply quote the Biological Society’s Vernon Bailey, who wrote this in 1923: “The psychological value of a defenseless wild animal in our midst to be protected, fed and guarded by the people through interest rather than by force of law, cannot be overestimated.”

Watch the fur fly

All this week we’ll be exploring the wide world of squirrels. For more coverage, go to washingtonpost.com/washingtology. You can send us photos you’ve taken of squirrels. Share your squirrel tales in the comments below. Or tweet your story (in 140 characters or less) on Twitter. Use #DCSquirrelWeek.

Send questions to answerman@washpost.com.